Modular cell and matrix for supporting a load bearing feature

ABSTRACT

A modular cell that may be used with other cells to form a matrix under a load bearing feature, the cell being a single piece molding that supports a compressive load placed thereon, the molding including a void space defined within: a skirt shaped support member defining a substantially planar surface with an opening therein; and at least one leg integral to and extending from the support member. The cell further includes at least one separate linking member that releasably links together multiple cells to form a matrix of cells. The cells may be linked together vertically and/or horizontally. The cell and matrix include greater load bearing capacity and rigidity through aligned legs to carry the weight as well as interlinking members that act to share the load among the various cells. The design also requires less material hence is cheaper to produce. The void space is also easily accessed hence allowing for easy access, filling and laying of utility lines where needed.

TECHNICAL FIELD

Described herein is a modular cell for supporting a load bearing featureand matrix formed from multiple cells. More specifically, a modular celland matrix are described herein to be used under a load bearing featuresuch as a roadway or walkway. Each cell, and collectively a matrix ofthe cells, contains a void space or spaces suitable for water collectionor to act as a rooting area for plants and trees.

BACKGROUND ART

A modular cell is described adapted to form a matrix of cells to supporta load bearing feature such as a roadway, pavement or walkway while atthe same time providing an area within the structural frame of the cellor matrix for a tree root network and/or service pipes. The cell matrixis sufficiently strong to not require filling and can instead be used asa reservoir or water collection area beneath a load bearing feature. Thecell or matrix aims to accommodate the combined needs of trees, treeroots, storm water run off, roadways, pavements and walkways so thatthey all can co-exist in their interaction within the urban and suburbanenvironment.

With respect to the rooting embodiment, there is a desire to introducetrees or plant matter into the landscape in order to make the urban andsuburban environment more aesthetically pleasing and more conducive togood healthy living.

Nonetheless it is well recognised that plants and especially largertrees require a certain amount of space within these populated areas ifthey are going to develop into mature plants offering the benefits ofshaded foliage, water retention, cooling, aesthetics and so forth to thesurrounding area. Trees are referred to hereafter but it should beappreciated that the same analogy may be made of plants generallyespecially for larger plants.

For the most part, town planning has seen the planting of trees in urbanand suburban areas to grow in close proximity to pavements and walkwaysso that the benefits of the trees can be enjoyed by those pedestriansutilising such features.

It is well recognised that for trees to successfully grow they requirenutrient rich soils with the appropriate levels of moisture andsufficient drainage to allow the tree's root system to pass therethrough.

Alternatively, roadways, pavements, walkways and the like require acompacted and well supported soil structure to keep the positionedpavers or concrete in place thereby avoiding any structural damage tothe construction and during the time of load bearing.

Hence if trees are going to be planted in urban and suburban areasaround roadways, pavements and/or walkways there may be a predicament asto whether or not one needs to look after the trees and thereby providelow compact soil suitable for root growth or alternatively compact soilswhich provide the necessary load bearing support for the relevantroadway, pavement and/or walkway which, as noted above, would make itunconducive for the root system of the tree to develop.

More efficient water usage and storage is also a pressing issue in dryseasons or in dry climates yet water run off may often be lost throughfailure to capture rain and the like.

There are also increasing environmental standards requiring the captureof pollutant run off from hard surfaces.

There also needs to be sufficient area available for utilities such aspiping and wiring to pass through the ground or other structures.

One solution described in PCT/AU2010/001034 is a modular cell adapted toform a structural frame of cells for supporting a load bearing featurewhile at the same time providing an area within the structural frame fora tree root network and/or service pipes. This design represented amajor improvement on the art especially in terms of strength and loadbearing capacity. One difficulty though was that the legs of this designalternated in position hence there was not a single continuous loadbearing member when multiple cells were stacked vertically. A furtherdifficulty was that the opening at the top of the modular cell waslimited in size and made it difficult to ensure soil transfer throughthe opening and into all void spaces in the cell. In addition the wallsof the cell could cause segmentation with water not flowing to all voidspaces and the cell walls could also restrict access for larger servicepipes to pass through the cells.

It should be appreciated that it would be useful to provide a modularcell and matrix using the cells which is able to accommodate the needsof both trees and utility lines and/or water collection and utilitylines, as well as meeting the physical engineering requirements ofsupporting a load bearing feature, or at least to provide the publicwith a choice.

Further aspects and advantages of the modular cell and matrix willbecome apparent from the ensuing description that is given by way ofexample only.

SUMMARY

Described herein is a modular cell and matrix formed using multiplecells for supporting a load bearing feature. A matrix formed using thecells is sufficiently strong to hold a load without filling of the cellvoid spaces hence may be used as a reservoir space or instead, may befilled with soil and the void space in the cells used to form a rootingarea underneath the load bearing feature.

In a first aspect, there is provided a modular cell adapted for use withother cells to form a matrix under a load bearing feature, the cellbeing a single piece moulding that supports a compressive load placedthereon, the moulding including a void space defined by:

-   -   (a) a skirt shaped support member defining a substantially        planar surface with an opening therein; and    -   (b) at least one leg integral to and extending from the support        member; and        wherein the cell is suitable to receive a separate linking        member or members to releasably link together multiple cells to        form a matrix of cells in both a vertical and a horizontal        plane.

In a second aspect, there is provided a matrix under a load bearingfeature, the matrix being made up of a plurality of modular cellssubstantially as described above wherein the cells are linked togethervertically and/or horizontally.

In a third aspect, there is provided a method of forming a load bearingmatrix using the cell substantially as described above, the methodincluding the steps of:

-   -   (a) excavating a pit area into which the matrix will be        positioned;    -   (b) creating a first horizontal layer of cells and        interconnecting the cells using the linking member or members;    -   (c) placing at least one further layer of cells onto the first        layer, aligning the leg or legs of each cell such that an        applied load is transferred continuously down through the legs        of the matrix structure and interconnecting the cells using the        linking member or members; and    -   (d) placing a load bearing feature over the matrix.

In a fourth aspect, there is provided a method of forming a load bearingmatrix using the cell substantially as described above, the methodincluding the steps of:

-   -   (a) excavating a pit area into which the matrix will be        positioned;    -   (b) creating a first vertical layer of cells and interconnecting        the cells using the linking member or members;    -   (c) placing at least one further layer of cells alongside the        first layer, aligning the leg or legs of each cell such that an        applied load is transferred continuously down through the legs        of the matrix structure and interconnecting the cells using the        linking member or members; and    -   (d) placing a load bearing feature over the matrix.

Advantages of the above described modular cell and matrix includegreater load bearing capacity and rigidity through aligned legs to carrythe weight as well as interlinking members that act to share the loadamong the various cells. The design also requires less material hence ischeaper to produce. The void space is also easily accessed henceallowing for easy access, filling and laying of utility lines whereneeded.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the modular cell and matrix will become apparent fromthe following description that is given by way of example only and withreference to the accompanying drawings in which:

FIG. 1 illustrates a perspective view of the modular cell without theseparate linking members;

FIG. 2 illustrates a perspective view similar to the representation inFIG. 1, but also including linking members in this embodiment being capsproviding a vertical linkage between cells and lateral elongated rodsproviding a horizontal linkage between cells;

FIG. 3 illustrates a perspective view showing the modular cellslaterally and vertically interconnected;

FIG. 4 illustrates a perspective view of an alternative embodiment of amodular cell with the linking members removed;

FIG. 5 illustrates a perspective view of a vertical linking member usedwith the cell of FIG. 4;

FIG. 6 illustrates a perspective view of a horizontal linking memberused with the cell of FIG. 4;

FIG. 7 illustrates a perspective view of a horizontal matrix of thecells of FIG. 4 linked together;

FIGS. 8a, 8b and 8c illustrate a perspective, plan and bottom view of ahorizontal and vertical matrix of the cells of FIG. 4 linked together;

FIG. 9 illustrates a section side view of cells nested together forstorage and transport;

FIG. 10 illustrates a section side view of cells linked about an unevensurface illustrating how the matrix can cater for variation in groundsurface contours;

FIG. 11 illustrates an alternative circular shaped support member withmating sections and linking members not shown;

FIG. 12 illustrates a cross-section of a matrix in situ;

FIG. 13 illustrates a perspective view from above of a grating that maybe used in a cell;

FIG. 14 illustrates a top view of a grating;

FIG. 15 illustrates a side view of a grating;

FIG. 16 illustrates a perspective view from below of a grating;

FIG. 17 illustrates a perspective view from above of a cell with agrating placed onto the top opening of the cell;

FIG. 18 illustrates a cross section perspective view of a cellincorporating a grating;

FIG. 19 illustrates a cell matrix with gratings placed on the top layerof cells;

FIG. 20 illustrates a perspective view of a cell with a base memberattached;

FIG. 21 illustrates a perspective view of one embodiment of a basemember; and

FIG. 22 illustrates a view from above of one embodiment of a basemember.

DETAILED DESCRIPTION

As noted above, described herein is a modular cell and matrix formedusing multiple cells for supporting a load bearing feature. A matrixformed using the cells is sufficiently strong to hold a load withoutfilling of the cell void spaces hence may be used as a reservoir spaceor instead, may be filled with soil and the void space in the cells usedto form a rooting area underneath the load bearing feature.

For the purposes of this specification, the term ‘about’ or‘approximately’ and grammatical variations thereof mean a quantity,level, degree, value, number, frequency, percentage, dimension, size,amount, weight or length that varies by as much as 30, 25, 20, 15, 10,9, 8, 7, 6, 5, 4, 3, 2, or 1% to a reference quantity, level, degree,value, number, frequency, percentage, dimension, size, amount, weight orlength.

The term ‘substantially’ or grammatical variations thereof refers to atleast about 50%, for example 75%, 85%, 95% or 98%.

The term ‘comprise’ and grammatical variations thereof shall have aninclusive meaning—i.e. that it will be taken to mean an inclusion of notonly the listed components it directly references, but also othernon-specified components or elements.

The term ‘load bearing feature’ and grammatical variations thereofrefers to roadways, pavements and walkways or other features on which aload such as a vehicle or structure may be applied.

The term ‘tooless’ or grammatical variations thereof refers to amechanism that does not require a separate tool to operate themechanism.

The terms ‘upper’ and ‘lower’ when used refers to the orientation of thecell when in situ i.e. legs facing towards the bottom of the pit, theleg endings being the lower portion of the cell in situ and the supportmember facing towards the load bearing feature, being the upper portionof the cell in situ.

In a first aspect, there is provided a modular cell adapted for use withother cells to form a matrix under a load bearing feature, the cellbeing a single piece moulding that supports a compressive load placedthereon, the moulding including a void space defined by:

-   -   (a) a skirt shaped support member defining a substantially        planar surface with an    -   (b) at least one leg integral to and extending from the support        member; and        wherein the cell is suitable to receive a separate linking        member or members to releasably link together multiple cells to        form a matrix of cells in both a vertical and a horizontal        plane.

The support member shape may be a circular or semi-circular skirt. Theskirt may be polygon shaped. In one embodiment, the skirt may besubstantially rectilinear polygonal shaped.

Multiple cells may be linked together via the linking member or memberstoolessly and without the need to use separate fasteners. As may beappreciated, this speeds assembly and avoids the added expense of labourand materials attributable to fasteners or tool use. Tooless assemblyalso keeps the assembly process simple and requires minimal skill toassemble.

When multiple cells are stacked vertically, the leg or legs of each cellmay substantially align vertically such that an applied compressive loadfrom a hard surface is transferred continuously through the legs of thematrix structure to a surface on which the matrix is placed. This designovercomes some of the drawbacks of art designs by offering a continuousload structure (the cell leg or legs).

The above design has a compression strength when in matrix format towithstand the weight of a load bearing feature (and any load on thatfeature) without needing to be filled or reinforced by other materialssuch as soil. The compression strength of the cell may be greater thanat least approximately 200 kPa. As may be appreciated, this compressionstrength may be equal to or greater than is typical for art celldesigns. The cell strength may be greater than or equal to approximately300 kPa. The matrix strength incorporating the cells may be higheragain—as may be appreciated, when the cells are linked together as amatrix, the cells share an applied load and therefore have a greaterstrength than one cell used alone.

The cell may be manufactured from plastic. The cell may be manufacturedfrom recycled plastic. The cell may be further strengthened by theaddition of glass fibres into the plastic. In the inventor's experience,introduction of glass fibres can double the compressive strength of thecell versus a non-glass fibre cell. As may be appreciated, use of glassfibres may be optional and only for high loading applications.

The above design further meets various loading standards without needingto choose specific soil fill type(s). The strength of some art cells maybe dependent on the aggregate profile used to fill the cells and thisaggregate profile is critical as the art cell structure itself may offerlittle strength. The cell structure described herein is strong enough tonot need any fill at all and support a load, or at least does notrequire the same care and attention of aggregate profile selection aswhat some art cells may require. As may be appreciated, the ability toavoid so much care in aggregate selection means the cell describedherein may be more versatile than the art as a range of soil/aggregatetypes may be used or, even no soil fill may be a useful embodiment forexample, where the cells are used to form a void space used as areservoir.

A further advantage of the above design is that it may be possible tominimise, or avoid altogether, compaction of soil used in the cellmatrix yet still achieve desired strength unlike art cells that mayrequire at least some compaction to gain the desired level ofcompression strength (up to 80% compaction).

Each cell may have a void space of at least approximately 80% of thecell volume. Each cell may have an unsegmented void space of at leastapproximately 80%. In one embodiment, the void space or space availablefor water storage or rooting space may be at least 85%. As may beappreciated, greater void space means more volume is available forrooting and/or liquid collection. Also important when considering voidspace is segmentation—some designs can have considerable void space butthat space is not available for rooting or for liquid storage. The abovedescribed cell has all of the described void space available and free ofsegmentation.

As noted above, the void space within the cell or cells may be filledwith soil and used to support a rooting area within the matrix. This isa typical application of such cells and the above described cell isparticularly useful for this owing to little segmentation of the voidspace within the cell whilst also improving load bearing strength.

The above described open void structure leads to easy flow of waterthroughout the structure thereby avoiding dry regions or segments withinthe cells.

A further advantage of the above design is that the cells, when inmatrix form, are easy to fill with soil since each cell support memberhas a sizable opening sufficient to allow easy tipping of soil into thevoid space and the opening is continuous through to the bottom of theexcavated area in which the cells are placed. Also, since there is acontinuous view through the openings to the base of the matrix, it ispossible to, from a viewpoint above a constructed matrix, visuallyinspect the bottom of a matrix for construction or inspection purposes,and observe that filling occurs in all void spaces.

As noted above, there is no need to specify any particular type of soil.The above cell design handles a range of soil types and unlike artdesigns, there is no need for specifying for example, use of sandy drysoils. It is envisaged that a range of soils may be added to the cellswithout difficulty including but not limited to loams (unscreened),moist soils, bio-retention soils and existing site soils. There is alsono need to vibrate the soil into the matrix voids although this could becompleted if desired.

In a further embodiment, the soil fill may instead be a filtrationmedia. For example, the filtration media may be activated charcoal,zeolite or other highly porous transfer medium. It is envisaged that thecell filled with such filtration media may be used to removecontaminants from incoming liquid thereby acting as a filter. Onceexample of this embodiment may be under or around milking sheds to catchliquid run off and the filter such run off prior to further treatments.Another example may be to use this filter embodiment around vehiclewashing stations and treat or part treat water run off from suchstations.

The actual area available for root growth may be substantially all ofthe full void volume. This is because there are no anticipated dry areasor areas that might not be filled with soil such as segmented regions.

As noted above, the void space within the cell or cells mayalternatively be used as a reservoir. This form of application is onlypossible due to the high compressive strength attained using the abovedescribed design. Reservoir applications may be to capture water ingeneral, stormwater run off, grey water or to capture pollutants orpolluted water from entering waterways such as rivers. In such reservoirembodiments, the pit in which the matrix is formed may be lined so as toprevent egress of water from the reservoir volume. The reservoir may bedesigned so as to capture all run off. The reservoir may instead bedesigned so as to capture and directionally release the liquid—forexample, water collected may be released in a trickle manner via tubingdirecting the liquid flow to plants neighbouring the cell matrix site.The reservoir may also be used as part of a flood control managementstrategy.

The void space within the cell or cells may be empty. In thisembodiment, the internal walls of the pit into which the cell or cellsare placed may be lined and for example used as described above tocollect rainwater therein.

At least one utility line may pass through the void space in the cell ormatrix of cells. Utility lines often pass through growing spaces and artproducts have had varying success in allowing easy access for utilitylines. The above described cell has continuous spaces for easy utilityline access and placement. Utility lines include piping for stormwatermanagement, sewerage management and water. Utility lines may alsoencompass wiring such as electrical wiring, phone wiring and so on—suchwires may be inside piping such as conduit piping.

The size of utility lines able to pass through the above described cellsmay be significantly larger than art designs. By way of example,utilities greater than or equal to approximately 5 inches in diametermay pass through a matrix made using the above described cells. Inselected embodiments, utility lines may be up to 200 mm in diameter. Theopen framework described gives flexibility and allows for both straightand flexible utility lines.

The overall cell size may be varied to suit the desired application but,by way of illustration, may be 300, or 400, or 500, or 600, or 700, or800, or 900, or 1000 mm in width from side to side of the planar supportsurface and approximately 100, or 200, or 300, or 400, or 500, or 600,or 700, or 800, or 900, or 1000 mm in height measured from the planarsupport surface to the distal end of a leg.

As noted above, the matrix formed using multiple cells may havecontinuous openings vertically and/or horizontally. This design in turnleads to either minimal or no segmentation issues and allows for acontinuous rooting volume.

In one embodiment, the leg ending or endings may be shaped to complementa depression or depressions in the support member of a second cell aboutthe interface between the support member of the second cell and the legor legs of the first. The cells may be linked together vertically via alinking member (termed hereafter as a ‘vertical linking member’)inserted between the leg ending or endings of a first cell and thedepression or depressions of a second cell. The depression may be in theform of a cavity. While direct linking between cells may also becompleted, the above approach of using a vertical linking member may beadvantageous for strength and versatility plus this allows the use ofhollow legs, a useful characteristic to decrease the amount of materialused to form the cells and to allow nesting of the cells duringtransport.

The leg or legs may have a cylindrical or semi-circular cross-sectionalshape although other polygonal shapes may also be used.

The depression or depressions in the support member may correspond to anat least partially hollow core within a leg or legs. In one embodiment,the leg or legs may be completely hollow.

The leg or legs may be at least partially tapered to narrow as the legextends from the support member. The leg or legs may taper linearlyinwards from the support member distal end (greatest width) to thedistal end or ends of the leg or legs (smallest width).

The vertical linking member may be a wedge adapted to engage the endingof a leg from a first cell and also engage the depression in the supportmember or hollow leg opening from an immediate cell situated below thefirst cell.

The wedge may be a circular cap adapted to frictionally fit the endingof the leg. The at least partly hollow opening of each leg (or supportmember depression) may include an internal collar on which the cap restswhen one modular cell is vertically mounted upon another cell.

The wedge or cap may have an internal rib configuration in order to linkor fixably fit the depression or leg hollow opening. Each wedge or capmay include an external shoulder adapted to rest upon the internalcollar of the hollow opening of the leg of a vertically adjacent modularcell.

The wedge provides the vertical connection between vertically mountedmodular cells and achieves a unique way to secure upper and lower cellsin the matrix. No fasteners or tools are required to link the separatecells, with the parts simply being lightly compressed together toachieve the linkage.

The cell may include at least one mating section (termed hereafter as a‘horizontal mating section’) as part of the moulding that releasablyengages one distal end of a linking member (termed hereafter as a‘horizontal linking member’) and wherein the opposing distal end of thehorizontal linking member engages a horizontal mating section of afurther cell thereby linking the cells in a horizontal plane. While theabove has been described in the context of the section or member being aseparate item, one or both of these parts may be integral to the supportmember and not separate parts.

The horizontal linking member may be an elongated rod. The elongated rodmay have a main horizontal body length defining the distance ofseparation in a horizontal plane between adjacent modular cells. Thedistance of separation may be equivalent to 20, or 30, or 40, or 50, or60, or 70, or 80, or 90, or 100, or 110, or 120, or 130, or 140, or 150%of the cell width. The distance of separation may be substantiallyequivalent to that of the width of a cell. Such a distance of separationmay be beneficial so as to limit the number of cells required to form amatrix thereby reducing material costs to form a matrix (for example,approximately 30-50% fewer cells required than if no horizontal linkingmembers were used).

The distal ends of the horizontal linking member may terminate withtabs. These tabs may complement and fit into the shape of the horizontalmating section(s) of the cell.

The horizontal mating section(s) may have a socket shape that receivesand fixably retains the tabs of the horizontal linking member(s).

The horizontal mating section(s) may be located at two engagementpoints, configured at substantially right angles to each other. The tworight angle engagement points may be located at each corner of thesupport member skirt thereby enabling modular cell construction toextend in all directions in a horizontal plane and for verticallyconstructed columns of modular cells to be evenly spaced in alldirections. In an alternative embodiment, one engagement point may beused located about the apex of at least one corner of the support memberskirt.

The use of the two engagement points configured at substantially rightangles at each corner of the support member skirt provides a convenientway in which the modular cells can be joined together. As noted above,single attachment points may be used but a double engagement point meanseasier building of a matrix and greater structural strength for a givenvolume of materials used. Placement of the engagement points at rightangles in conjunction with the support member shape means that themodular cell does not have to be aligned or adapted in any particularorientation as a universal fit becomes available allowing a simple andstraightforward task in the construction of the structural frame bothvertically and laterally. Alternative arrangements of engagement pointsfor support members having other shapes (e.g. hexagonal) are encompassedherein as should be appreciated by the skilled person. Ultimately,engagement points may ideally be arranged such that a matrix canextended in all directions.

The modular cells can be installed with or without the horizontallinking members. When the horizontal linking members are used, the endstructure is an interconnected matrix with a great deal of strength andrigidity. Also, despite using an interconnected structure, the parts areeasy to separate if needed, such as when an area is excavated. Themodular nature of the cells and separate linking members means that itis easy to remove a small section of the matrix or even an individualcell from the matrix. It is not necessary to remove big portions of thematrix although this too is possible if desired. Interlinking duringassembly also helps to retain the cells in position during the assemblyprocess.

The horizontal linking members may also provide tolerance to managecontour variation on a horizontal support surface. As may beappreciated, a pit into which the cells are placed may not be perfectlyflat. The connecting members between cells may be sloped between cellsthereby addressing height variation in cells due to uneven ground. Inone embodiment, the slope of the horizontal linking member may be atleast 1, or 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10 degreesfrom a horizontal plane.

The cells may be shaped so that multiple cells may be nested togetherfor storage and transportation. As noted above, the leg or legs may becharacterised by having a substantially hollow core and taperedlength—in this embodiment, the leg or legs of one cell may fit into thehollowed leg or legs of a subsequent cell and by fitting the cellstogether about the legs, the cells may be nested closely together inthis manner. Linking members (horizontal and vertical) may be storedand/or transported separately, these parts being comparatively small. Abag of such linking members may for example be placed inside the voidspace of one bottom-most cell in a nested stack of cells.

In a further embodiment, vertical linking members may be fitted at theinterface between the base of the legs of the cells on the bottom mostlayer of the matrix and the substrate on which the matrix is placed. Itis envisaged that this embodiment may be useful to increase the loadrating of the matrix applicable in potentially high loadingapplications. As should be appreciated, it is not essential to use thevertical members on the leg endings and for lower loading applications,the linking members may not be present.

A cell or cells may also optionally include a grating.

The grating may be of a suitable size to engage the opening in the topof a cell defined within the skirt shaped support member. In selectedembodiments, the grating circumference is sufficiently large that, whenfitted to a cell, the grating may be a snug fit into the cell opening.The grating may include a solid border region with members inside theborder region defining a grating matrix or mesh pattern. The meshpattern region may be slightly recessed into the cell opening whenfitted to a cell relative to the border region of the grating. The meshpattern members may include two thicker members that define the centralintersecting members and other relatively thinner members surroundingthese thicker members. The exterior of the grating border region mayhave an inverted L-shape, the acute angle region or interior of theL-shape conforming to the shape of the cell opening. Part of the L-shaperegion may extend from the solid border region of the grating to form alip or flange that engages the edge of the cell opening and prevents thegrating from falling through the cell opening. When fitted, the gratingmay rest approximately flush with the cell top.

The grating may include an enlarged corner so as to assist with handlingthe grating when placing the grating onto a cell or when removing thegrating from a cell.

The walls of the L-shape interior may include rib elements to increasethe strength and rigidity of the grating. The rib elements may alsoassist with ensuring a snug fit of the grating into the cell openingand, via friction between the grating rib elements and cell opening,prevent the grating from disengaging the cell.

When gratings are used in a matrix of cells, they may be placed on thetop cell layer only and lower layers may not have the gratings.

In an alternative embodiment, the cell opening may have a recessedinternal shoulder that acts to support a grating placed into the cellopening void.

An aim of the gratings may be to support particular geo-compositesand/or paving. Gratings provide a greater surface area on which asubstrate such as a path or road or tiles may be placed and minimisevoid space underneath—the result is the avoidance of localised slumpingor even holes in the substrate about a cell opening void. Gratings mayalso give extra strength and rigidity to the cell and/or matrix plus thehelp to distribute compressive load across matrix and not just on singlecells or single cell legs.

Use of gratings may be optional dependent on the loadings needed plusdepth of matrix—for example, gratings may be more critical if the top ofthe cell matrix top is close to the surface.

In use, the cell gratings may be dropped or slotted into the cells priorto a substrate layer being placed over the matrix. If the cell matrix isto be used for root growth, soil may be filled into the cells and/ormatrix, and the gratings fitted last.

The mesh spacing of the grating may be sized sufficient to let waterpass through yet also give structural strength to dissipate load amongmultiple cells. The grating pattern used may be varied and/or optimisedto suit minimise materials and therefore cost yet also providesufficient strength and rigidity. It should be appreciated that a crosshatch pattern is one means for achieving this optimum but that otherpatterns such as a bike spoke pattern may also be used.

The gratings may be made from the same materials as the cells.

A base member may be placed between the cell or bottom layer of cells ina cell matrix and a substrate on which the cell or matrix of cells areplaced.

As may be appreciated from the above description of the vertical linkingmembers, these members may be fitted between the base of a cell leg orlegs and the ground or substrate on which the cell or cells are placed.Use of individual linking members like this may be beneficial to spreadthe point load from a leg or legs onto the substrate and avoid localiseddeformation in the cell or matrix level.

Other base load distribution parts may also be used instead of thevertical linking members. The base may be a tray on which the cell orcells are placed. The base member may be formed as a single piece skirtshaped member with a central opening and wherein each leg of the celllinks with an enlarged section on the base member.

The base may be a member to interlock or engages the base of one or morelegs. The interlocking/engagement may be via the leg endings snuglyfitting into a receiving portions on the base in the manner of a male(leg) and female (base upstand) fitting.

The base may include at least one aperture.

In one embodiment, the base is formed as a skirt shaped member with anopening therein and enlarged section in the member about theinterlinking region or regions of the member that link with the leg orlegs of the cell. The skirt shaped member may include four sidescomplementing the shape of the opening in the cell skirt.

Enlarged sections about the leg ending may be used on the basecomplementary to legs of a cell. The enlarged sections may be of acircular shape. The enlarged sections may have a diameter approximately1 (the same), or 2, or 3, or 4 times larger than the diameter of the legending. Each enlarged section may be linked to form the skirt shapedmember using elongated rods.

The base may be formed as a single piece, placed onto the substrate onwhich the cell or cell matrix are to be built and the cell then fittedto the base.

It is envisaged that the base may only be used on the bottom of a cellmatrix however this should not be seen as limiting as the base could beinserted for example between cell layers to segregate layers in thematrix.

The base member may be manufactured from plastic and moulded into thedesired shape.

An advantage of using the above base is to spread the point load(compressive downwards force from the load bearing feature) from the legending(s) to the ground or substrate on which the cell or cell matrix isplaced. A further advantage of a base may be to minimise and/or avoidlocalised slumping or level variation in the cell or cell matrix due toa leg or legs depressing into the substrate. A further advantage of thebase may be to provide extra rigidity to the legs of the base cellpreventing them from splaying out or in relative to the normal(un-splayed) position.

In a second aspect, there is provided a matrix under a load bearingfeature, the matrix being made up of a plurality of modular cellssubstantially as described above wherein the cells are linked togethervertically and/or horizontally.

In a third aspect, there is provided a method of forming a matrix undera load bearing feature using a cell substantially as described above,the method including the steps of:

-   -   (a) excavating a pit area into which the matrix will be        positioned;    -   (b) creating a first horizontal layer of cells and        interconnecting the cells using the linking member or members;    -   (c) placing at least one further layer of cells onto the first        layer, aligning the leg or legs of each cell such that an        applied load is transferred continuously down through the legs        of the matrix structure and interconnecting the cells using the        linking member or members; and    -   (d) placing a load bearing feature over the matrix.

In a fourth aspect, there is provided a method of forming a matrix undera load bearing feature using a cell substantially as described above,the method including the steps of:

-   -   (a) excavating a pit area into which the matrix will be        positioned;    -   (b) creating a first vertical layer of cells and interconnecting        the cells using the linking    -   (c) placing at least one further layer of cells alongside the        first layer, aligning the leg or legs of each cell such that an        applied load is transferred continuously down through the legs        of the matrix structure and interconnecting the cells using the        linking member or members; and    -   (d) placing a load bearing feature over the matrix.

In the above aspects, before step (c) or step (d), the void spacedefined within the cell matrix may be filled with soil. Morespecifically, one horizontal or vertical layer may be assembled andfilled with soil and then a subsequent layer placed on top or alongsidethe first filled layer that is then in turn filled. Alternatively, afull matrix horizontally and vertically may be assembled and then filledwith soil prior to placing the load bearing feature such as a roadsurface on top of the matrix.

Alternatively, before step (b), the pit area may be lined and thenassembly of the matrix occurs as described above. No soil or fill isplaced within the matrix formed and the void space within the cells isused a reservoir space to retain for example, stormwater run off.

During steps (b) or (c) above, a utility line or lines may be placedwithin the cell matrix void space.

Steps (b) and (c) may be completed toolessly and do not require anyspecial tools or fasteners to complete.

Optionally, in the above methods, after step (c) and before step (d),the top of the cell matrix may have a grating or gratings placed intothe openings of the top most cells.

Advantages of the above described modular cell and matrix using the cellinclude greater load bearing capacity and rigidity through aligned legsto carry the weight as well as interlinking members that act to sharethe load among the various cells. The design also requires lessmaterial, may be assembled without tools and does not require separatefasteners to retain the matrix together hence is inexpensive and simpleto produce and assemble. The void space is also easily accessed henceallowing for easy access, filling and laying of utility lines whereneeded.

The embodiments described above may also be said broadly to consist inthe parts, elements and features referred to or indicated in thespecification of the application, individually or collectively, and anyor all combinations of any two or more said parts, elements or features,and where specific integers are mentioned herein which have knownequivalents in the art to which the embodiments relates, such knownequivalents are deemed to be incorporated herein as of individually setforth,

Where specific integers are mentioned herein which have knownequivalents in the art to which this invention relates, such knownequivalents are deemed to be incorporated herein as if individually setforth.

WORKING EXAMPLES

The above described modular cell and matrix are now described byreference to specific examples.

Example 1

FIG. 1 shows an embodiment of the modular cell (10) including a supportmember being a main upper substantially rectilinear polygon shapedmember shown as (12) which includes four sides (14) establishing a mainsupport body that includes an upper opening (16).

The sides (14) of the support member (12) have at each corner,cylindrical columnar legs (20).

Each leg (20) has a hollow core shown by way of (23) and tapered sideedge (21) such that when the modular cells are stacked, for exampleduring storage and/or transportation each of the respective cylindricalcolumnar legs (20) can nest with the hollow core (23) of a correspondingmodular cell.

The modular cell (10) further includes an internal collar (25) which asshown in FIG. 2 works in combination with a vertical linking membershown in this embodiment as a cap (26) to engage a peripheral end (34)of the cylindrical leg (20) of a corresponding modular cell (10) whenthe modular cells (10) are mounted vertically one upon the other.

Each cylindrical leg (20) includes two horizontal mating sections orengagement locations (22) and (24) substantially at right angles to eachother which are illustrated in greater detail in FIG. 2. Theseengagement locations (22) and (24) allow for the horizontal linkingmember shown in this embodiment as an elongated rod (32) to engage therespective slots (40) and (42) of each of these engagement points (22)and (24) so that the modular cells (10) can be laterally engaged.

Circular caps (26) which include an internal ribbing (28) are adapted toengage the general base peripheral area (34) of each cylindrical leg(20).

This circular cap (26) on its external surface includes a shoulder (30)which is configured so as to rest and fix in place upon the internalcollar (25) on the upper circular edge of a corresponding (i.e. second)modular cell (10) below the modular cell (10) which are stackedvertically one upon the other.

The introduction of the cap (26) provides secure connections betweenupper and lower modular cells (10). Further, with the respectivecylindrical legs (20) aligned, the overall ultimate crush strength ofthe frame structure once constructed is increased.

As best seen in FIG. 3, the modular cell (10) when vertically connectedbetween upper and lower modular cells (10) has the cylindrical legs (20)aligned such that an applied load or crush load is transferred directlydown through the aligned cylindrical legs (20) providing improvedstructural integrity to the assembled matrix of cells (10).

The horizontal linking members (32) include a main horizontal or laterallength (36) which can define the spacing laterally between joinedmodular cells. At each distal end (38 a) and (38 b) the horizontallinking member has tabs which are adapted to be inserted into thecorresponding slot (40) or (42) of the pair of engagement points (22)and (24) on each cylindrical leg (20). The lateral length (36) of thehorizontal linking members (32) may be approximately equivalent to themodular cell (10) width.

The horizontal linking member arrangement allows the modular cells (10)to be interconnected in a complete frame structure matrix. Columns orlegs (20) become evenly spaced in all directions with no pre-alignmentrequired i.e. establishment of the two engagement points substantiallyat right angles on each of the cylindrical legs (20) positioned at eachof the edges of the support member (12) provide a means and mechanism inwhich the frame structure can be constructed vertically by mountingupper and lower modular cells together through the use of the cap (26)and then inter-connecting evenly spaced modular cell laterally in alldirections through the connector members (32).

The support member defines an opening (16) that offers a greater area inthe top of the modular cell (10) to permit soil to be loaded more easilythere through.

The larger openings shown by way of (18) between the respectivecylindrical columnar legs (20) provides a larger space for both the treeroot network and also service pipes to be able to pass there through.

Example 2

FIGS. 4 to 10 illustrate an alternative shape of cell and linkingmembers used to form a matrix.

The cell generally indicated by arrow (50) includes a support memberregion (51) and legs (52). In this embodiment the horizontal matingsections (53) for horizontal linking members (56) are shaped as squaresrather than as circles as in FIGS. 1 to 3.

FIG. 5 shows a vertical linking member (54), again being a cap as inFIGS. 1-3 but with a slightly different shape including an upwardlyextending protrusion (55). This protrusion (55) may mate with acomplementary hole (not shown) in the base of a leg (52) of the cell(50).

FIG. 6 show a horizontal linking member (56) in this embodiment being anelongated rod with squared endings that mate with the horizontal matingsections (53) on the cell (50).

FIG. 7 shows a horizontal matrix of cells (50) linked together using theelongated rods (56). Caps (54) are shown inserted into the top of thelegs (52). The bases of the legs (52) also include caps (54) with theprotrusion (55) of each leg (52) inserted into a complementary hole (notshown) in the base of the leg (52). Using caps as part of the base maybe useful in high loading situations but may not be required in lowerloading applications.

FIGS. 8a, 8b and 8c show a dual horizontal and vertical matrix of cells(50). As can be seen, the matrix includes distinct openings (57)vertically and horizontally through which soil and/or utility lines maypass.

FIG. 9 illustrates how the cells (50) may be nested together for ease ofstorage and transportation. Being able to nest multiple cells (50)together considerably reduces the volume thereby reducing transportationcosts and making the cells easier to store.

FIG. 10 illustrates how the ground on which the cells are placed doesnot need to be completely flat and some variation in ground contour canbe catered for. As shown in FIG. 10, the space between different cells(50) is spanned by a rod or rods (56). The rods may be on an angle (59)to a horizontal plane meaning the interconnecting cells (50) may beoffset by distance (58).

Example 3

As noted above, the skirt shaped support member may be in varyingshapes. FIGS. 1 to 10 illustrate a rectilinear polygon shaped skirt.FIG. 11 illustrates an alternative circular skirt shape general shown byarrow (100). As can be seen in FIG. 11, the support member (101) stillincludes similar features of a substantially planar surface (102) withan opening (103) and legs (104) extending from the support member (101).

Example 4

FIG. 12 illustrates an elevation cross-section view of a cell matrixinstallation. A pit generally indicated by arrow (201) is dug intocompacted soil (202) surrounding the cell matrix (203) area. The cellmatrix area is filled with soil (not shown) into which a tree (204) isplanted. A load bearing feature (205) such as a footpath is laid overthe cell matrix (203). The tree (204) is able to grow in the soilcontained within the cell matrix (203). The cell matrix (203) supportsthe load bearing feature (205) and any load thereon such as pedestrians,vehicles and the like (not shown).

Example 5

FIGS. 13 to 19 illustrate a further variation in the design wheregratings may be used. Gratings 300 may be helpful as a means todistribute a load force across the whole cell 301 or multiple cells 301in a matrix 301A.

The grating 300 may be of a suitable size to engage the opening in thetop of a cell 301. The grating 300 includes a solid border regiongenerally indicated by arrow 302 with thinner members 303 inside theborder region 302 defining a grating matrix. The thinner members 303 mayinclude two thicker members 304 that define the central intersectingmembers and relatively thinner members surrounding these thicker members304. The exterior of the grating border region 302 is an invertedL-shape generally indicated by arrow 305, the interior of the L-shapeconforming to the shape of the cell 301 opening generally indicated byarrow 306. Part of the L-shape forms a lip 307 that prevents the gratingfrom falling through the cell 301 opening.

The grating 300 may include an enlarged corner 308 so as to assist withhandling the grating 300 when placing the grating 300 onto a cell 301 orwhen removing the grating 300 from a cell 301.

The walls of the L-shape interior 305 may include rib elements 309 toincrease the strength and rigidity of the grating 300. The rib elements309 may also assist with ensuring a snug fit of the grating 300 into thecell 301 opening and, via friction between the grating 300 rib elements309 and cell 301, prevent the gratings 300 from accidentally disengagingthe cell 301.

As shown in FIG. 19, when gratings 300 are used, they may be placed onthe top cell 301 layer only and lower layers do not have the gratings300.

Example 6

FIGS. 20-22 illustrate one form of base 400 that may optionally be used.In the example shown, the base 400 is formed as a single piece skirtshaped member with a central opening 402. Each leg 401 of the cell 404fits a complementary enlarged section 405 in the base 400. Multiplecells 404 may be used stacked on top or alongside the cell 404 shown inFIG. 20. For clarity, other cells in the matrix are not shown.

The legs 401 and base 400 enlarged sections 405 interlock or engage viathe leg 401 endings 403 snugly fitting into receiving portions 406 onthe base 400 in the manner of a male (leg 401) and female (receivingportion 406) fitting. Other means to link the parts (401,400) may beused but a simple snug fit is sufficient to spread the compressivedownwards force on the leg 401 and retain the leg 401 and base 400together.

The enlarged sections as shown are circular in shape. As illustrated,the enlarged sections 405 may have a diameter approximately three timeslarger than the diameter of the leg 401 ending 403—this particular ratiohas been identified as a useful balance of strength, load distributionand minimisation of materials and parts. Each enlarged section 405 islinked using elongated rods 407 to form the base 400.

The base 400 may be formed as a single piece, placed onto a substrate(not shown) on which the cell 404 or cell matrix are to be built and thecell 404 then fitted to the base 400. The base 400 may be manufacturedfrom plastic and moulded in the shape shown.

Aspects of the modular cell and matrix have been described by way ofexample only and it should be appreciated that modifications andadditions may be made thereto without departing from the scope of theclaims herein.

What is claimed is:
 1. A modular cell adapted for use with other cellsto form a matrix under a load bearing feature, the cell being a singlepiece moulding that supports a compressive load placed thereon, themoulding including a void space defined by: (a) a skirt shaped supportmember defining a substantially planar surface with an opening therein;and (b) at least one leg integral to and extending from the supportmember wherein at least one leg has an ending or endings which areshaped to complement a depression or depressions in the upper surface ofa second or further cell, the depression or depressions located aboutthe interface between the upper surface of the second cell and the legor legs of the first cell, and wherein the cells are linked together viaa vertical linking member inserted between the leg ending or endings ofthe first cell and the depression or depressions of the second, cell thevertical linking member being a cap adapted to frictionally fit thedepression or depressions and having an internal rib configuration tofixably fit the cap to a leg ending; and wherein the cell is suitable toreceive a separate linking member or members to releasably link togethermultiple cells to form a matrix of cells in both a vertical and ahorizontal plane; and wherein the cell or cells include at least onemating section as part of the moulding that releasably engages onedistal end of the separate linking member and wherein the opposingdistal end of the linking member engages at least one mating section ona further cell thereby linking the cells horizontally.
 2. The cell asclaimed in claim 1 wherein the depression or depressions correspond toan at least partially hollow core within a leg or legs.
 3. The cell asclaimed in claim 1 wherein the mating section or sections are located onor about the cell support.
 4. The cell as claimed in claim 1 wherein thehorizontal plane linking member or members create a distance ofseparation between the cells.
 5. The cell as claimed in claim 4 whereinthe horizontal plane linking member length is equivalent to between 20to 150% of the cell width.
 6. The cell as claimed in claim 3 having atleast two horizontal mating sections wherein the mating sections arelocated at two engagement points, configured at substantially rightangles to each other.
 7. The cell as claimed in claim 1 wherein, whenmultiple cells are stacked vertically, the leg or legs of each cellsubstantially align vertically such that an applied compressive loadfrom a hard surface is transferred continuously through the legs of thematrix structure to a surface on which the matrix is placed.
 8. The cellas claimed in claim 7 wherein the compression strength of the cell isgreater than at least 200 kPa.
 9. The cell as claimed in claim 1 whereineach cell has a void space of at least approximately 80%.
 10. The cellas claimed in claim 1 wherein each cell has an unsegmented void space ofat least approximately 80%.
 11. The cell as claimed in claim 1 wherein,during storage and/or transportation, multiple cells nest together. 12.The cell as claimed in claim 1 including a grating or gratings in thecell top opening.
 13. The cell as claimed in claim 1 including a basemember adapted for placement between the cell, or bottom layer of cellsin a cell matrix, and a substrate on which the cell or matrix of cellsare placed.
 14. A matrix under a load bearing feature, the matrix beingmade up of a plurality of modular cells as claimed in claim 1 linkedtogether vertically and/or horizontally.
 15. A modular cell adapted foruse with other cells to form a matrix under a load bearing feature, thecell being a single piece moulding that supports a compressive loadplaced thereon, the moulding including a void space defined by: (a) askirt shaped support member defining a substantially planar surface withan opening therein; and (b) at least one leg integral to and extendingfrom the support member; and wherein: the cell is suitable to receive aseparate linking member or members to releasably link together multiplecells to form a matrix of cells in both a vertical and a horizontalplane; the leg ending or endings are shaped to complement a depressionor depressions in the upper surface of a second or further cell; and thevertical linking member is a cap adapted to frictionally fit thedepression or hollow.
 16. The modular cell of claim 15 wherein: thehorizontal plane linking member or members are linked to the cell andcreate a distance of separation between the cells.